(Internet slang) Used to avoid specifying the reasons for something, perhaps because specifying them would be tangential to the point at hand, or perhaps the reasons are too many or too involved or too time consuming to specify, or perhaps because they are not sound or are not known to the speaker.

(philosophy) The use of reason to decide how to act.

(Roman Catholicism) Seven years of age, at which age a person is morally liable for the sins that he or she commits.

A doctrine in antitrust law which applies to contracts which "unreasonably" inhibit trade.

(obsolete) To be right. / To have grounds, justification etc. (to do something, or for something).

Alternative form of age of reason

plural of reasonable doubt

To an extent which is reasonable; not beyond what is reasonable.

(law) A degree of uncertainty to which a reason can be assigned; in those jurisdictions influenced by English common law, the minimum degree of uncertainty required to acquit a defendant.

(nonce word) A twofold or double reason.